Buck converters are commonly used to change the voltage or polarity of a DC power supply. Typically, a buck converter has several phases connected in parallel, with each phase having two switches (top and bottom switches) connected to an inductor. Such multiple phase buck converters are well known in the art and are commonly used for providing regulated DC power for microprocessors, telecommunications electronics and the like.
In recent years it has been discovered that efficiency and transient response of a multiple phase buck converter can be improved by coupling the inductors of several phases. Coupled inductors tend to decrease output current ripple, and thereby reduce the conduction loss in the switches. However, the extra conductor windings required for the coupled inductors increases the DC (ohmic) resistance of the circuit, which adversely affects the energy conversion efficiency.
It would be an advance in the art of voltage converter design to provide a multiple phase buck converter, boost converter, or buck-boost converter having coupled inductors with exceptionally low ohmic resistance. Such a voltage converter would have exceptionally high power conversion efficiency, fast transient response, and lower cost.